Comparison Guide
EIN vs CRN Compared
Understand the difference between a US EIN and a United Kingdom CRN. An EIN is a US federal tax ID. A CRN is a UK company registration number. They serve different countries.
Last updated: June 2, 2026
UK entrepreneurs expanding into the US market meet both identifiers fast. The EIN appears the moment you form a US LLC or corporation. The CRN already sits on your Companies House record. The two numbers look similar but answer to different governments. This guide compares them side by side, explains who needs each, and shows how UK founders get a US EIN without an SSN.
The core distinction is jurisdiction. The US Internal Revenue Service (IRS) issues the EIN for US federal tax. Companies House issues the CRN for UK company registration. Neither number works in the other country. You cannot swap one for the other.
| Factor | EIN (United States) | CRN (United Kingdom) |
|---|---|---|
| Full name | Employer Identification Number | Company Registration Number |
| Issuing authority | IRS | Companies House |
| Format | XX-XXXXXXX (9 digits) | 8 digits, or 2 letters + 6 digits |
| Primary purpose | US federal tax identification | UK company registration |
| Cost | $0 from IRS / $49 via ein.so | UK incorporation fee (confirm at Companies House) |
| Validity | United States only | United Kingdom only |
| Application route | Form SS-4 to the IRS | Incorporation at Companies House |
Definition
What Is an EIN?
An EIN (Employer Identification Number) is a 9-digit federal tax ID issued by the IRS to businesses operating in the United States. The format is XX-XXXXXXX, for example 12-3456789. The IRS assigns the number permanently once it issues it.
Every US business entity uses the EIN for federal tax filing, opening a US bank account, hiring staff, and accepting payments. The EIN costs $0 from the IRS. ein.so charges $49 to file Form SS-4 for non-residents who cannot use the IRS online tool. For a full explanation, read what is an EIN.
Key EIN Facts
A non-resident enters a passport number on Form SS-4 Line 7b. No SSN or ITIN is required. See how to get an EIN without an SSN.
Definition
What Is a CRN?
A CRN (Company Registration Number) is an 8-character identifier issued by Companies House when a company incorporates in the United Kingdom. England and Wales companies use 8 digits, such as 12345678. Scotland companies use SC plus 6 digits. Northern Ireland companies use NI plus 6 digits.
The CRN is a company registration identifier, not a tax number. Companies House assigns it at incorporation and never changes it. The number appears on the public register, on Companies House filings, and on official company documents. It identifies the company entity for corporate filings such as annual confirmation statements and accounts.
UK companies also hold a UTR (Unique Taxpayer Reference) from HMRC for tax. The CRN and the UTR split two jobs: the CRN registers the company, the UTR handles tax. In the US, the EIN performs both jobs in a single number.
Key CRN Facts
- Issued by: Companies House
- Format: 8 digits, or 2 letters + 6 digits (12345678, SC123456, NI123456)
- Country: United Kingdom only
- Purpose: company registration and corporate identification
- Tax counterpart: the HMRC UTR handles UK tax, not the CRN
Comparison
EIN vs CRN: Side-by-Side
An EIN identifies your business to the US government for tax. A CRN identifies your company to the UK government for the register. The table below sets out every practical difference between the two identifiers.
| Factor | EIN (United States) | CRN (United Kingdom) |
|---|---|---|
| Full name | Employer Identification Number | Company Registration Number |
| Issuing authority | IRS (Internal Revenue Service) | Companies House |
| Format | XX-XXXXXXX (9 digits) | 8 digits, or 2 letters + 6 digits |
| Country of validity | United States | United Kingdom |
| Is it a tax number? | Yes | No (the HMRC UTR is the tax number) |
| Cost | $0 IRS / $49 via ein.so | UK incorporation fee |
| When you receive it | After filing Form SS-4 | At UK incorporation |
| Used for banking | Yes, for US bank accounts | Yes, for UK bank accounts |
| Used for payment processors | Yes, Stripe and PayPal US | UK processor onboarding |
| Application document | Form SS-4 | Companies House incorporation |
| Who issues to non-residents | IRS accepts non-residents | Companies House accepts non-residents |
| Changes over time | Permanent | Permanent |
Where the Two Identifiers Overlap
Both numbers are permanent. Both identify a legal entity. Both unlock a domestic bank account and payment onboarding in their own country. The overlap stops there. The EIN reports to the IRS. The CRN sits on the Companies House register. One does not substitute for the other in any scenario.
For UK Founders
How Do UK Entrepreneurs Get a US EIN?
UK entrepreneurs get a US EIN by submitting IRS Form SS-4 by fax to 855-215-1627 and entering their UK passport number on Line 7b. The IRS online tool requires an SSN, so UK applicants use the fax method. The IRS issues most correctly filed EINs within 4-7 business days.
Form Your US Entity
Complete Form SS-4
Submit by Fax to the IRS
Receive Your EIN
Your CRN plays no part in this application. The IRS does not ask for or verify a UK CRN, UTR, or VAT number. Your passport is sufficient identification on Line 7b.
For deeper detail, read how to get an EIN, EIN for non-US residents, and the full SS-4 form guide.
Cost & Timing
How Much Does the EIN Cost Compared to a CRN?
The IRS charges $0 for an EIN. ein.so charges $49 for Standard service or $97 for Express to prepare and fax Form SS-4 and deliver your EIN by email. The UK CRN cost is the standard Companies House incorporation fee, which you pay once at registration.
The fee difference reflects what each number does. The EIN is a federal tax ID assigned through a single IRS form. The CRN is part of the broader act of incorporating a UK company. The table below compares the EIN options that ein.so offers.
| Service | Price | Delivery | Best for |
|---|---|---|---|
| IRS direct (DIY fax) | $0 | 4-7 business days if error-free | Founders comfortable formatting SS-4 alone |
| ein.so Standard | $49 | 4-7 business days | Most UK applicants |
| ein.so Express | $97 | 2-3 business days | Founders on a banking deadline |
The DIY route costs nothing in IRS fees, but a single address or Line 7b error means a silent rejection and weeks of delay. ein.so reformats your UK address to an IRS-accepted style and checks every field before faxing. Compare options on EIN cost and review EIN processing time.
Who Needs What
Do You Need Both Numbers?
You need an EIN if you run a US entity, and you need a CRN if you run a UK company. You need both if you operate in both countries. The lists below show which identifier each situation requires.
You Need an EIN
You Need a CRN
You Need Both
Order of Acquisition
The two numbers coexist without conflict. A UK resident keeps the CRN for the UK company and uses the EIN for the US LLC. Neither filing affects the other.
Banking & Tax
How Does the EIN Affect US Banking and Tax?
The EIN unlocks a US business bank account and US payment processors, which a CRN cannot do in the United States. Mercury, Relay, and Wise approve most non-resident LLC owners who hold an EIN and a passport. The EIN also drives US federal tax compliance.
A foreign-owned single-member US LLC files Form 5472 with a pro-forma Form 1120 each year. The penalty for not filing is $25,000. This is an information return, not always a tax bill.
Annual US Filings for a Foreign-Owned LLC
- File Form 5472 with a pro-forma Form 1120 every year, or risk a $25,000 penalty.
- File your BOI report with FinCEN for most US LLCs.
- Confirm your specific obligations with a US CPA, because ein.so does not provide tax advice.
Your CRN and UTR cover UK reporting at Companies House and HMRC. Those filings stay separate from your US filings. Use your EIN to open a US bank account and connect payment rails after approval.
Next Steps
What Should You Do Next?
A UK founder who forms a US entity needs an EIN, not a CRN, to operate in the US. The CRN stays with the UK company. The steps below cover what to do once you receive your EIN.
- Open a US bank account — Mercury, Relay, and Wise accept non-resident LLC owners with an EIN and passport.
- File your BOI report — required for most US LLCs at fincen.gov/boi.
- File Form 5472 — annually for a foreign-owned LLC, with a $25,000 penalty for non-filing.
- Apply without an SSN — read EIN without SSN and EIN for non-residents.
- Check timing and cost — see EIN processing time and EIN cost.
More comparisons: EIN vs ITIN | EIN vs SSN | EIN vs Tax ID. UK guide: EIN for UK entrepreneurs.
Frequently Asked Questions
Is an EIN the same as a CRN?
No. An EIN is a 9-digit US federal tax ID issued by the IRS in the format XX-XXXXXXX. A CRN is an 8-character company registration number issued by Companies House in the United Kingdom. Different authorities, different countries, different purposes. An EIN identifies a business for US tax. A CRN identifies a company on the UK register.
Do I need both an EIN and a CRN?
You need both only if you operate companies in both the US and the UK. Your EIN identifies your US LLC or corporation to the IRS. Your CRN identifies your UK limited company at Companies House. A UK resident who forms a US LLC keeps the CRN for the UK company and adds an EIN for the US entity.
Can I use my CRN instead of an EIN in the US?
No. The IRS does not accept a UK CRN for US tax reporting. A US LLC or corporation must obtain its own EIN from the IRS, regardless of any CRN you hold in the UK. The CRN has no standing with the IRS, US banks, or US payment processors. You file Form SS-4 to get the EIN.
How do UK entrepreneurs get a US EIN?
UK entrepreneurs submit IRS Form SS-4 by fax to 855-215-1627 and enter their UK passport number on Line 7b. No SSN or ITIN is required. The IRS online tool requires an SSN, so the fax method is the path for UK applicants. ein.so prepares and faxes the SS-4 for $49 Standard (4-7 business days) or $97 Express (2-3 business days).
What format is a CRN versus an EIN?
A CRN uses 8 digits (for example 12345678) or 2 letters plus 6 digits (for example SC123456 for Scotland, NI123456 for Northern Ireland). An EIN uses the format XX-XXXXXXX, which is 9 digits with a hyphen after the second digit. The two formats are not interchangeable and cannot be converted.
Is an EIN valid in the United Kingdom?
No. An EIN is valid only for US federal tax purposes and has no legal standing in the United Kingdom. A CRN has no standing in the United States. Companies House does not recognize an EIN, and the IRS does not recognize a CRN. Each country issues and accepts only its own business identifiers.
Is a CRN a tax number like an EIN?
No. A CRN is a company registration identifier, not a tax number. UK companies also receive a UTR (Unique Taxpayer Reference) from HMRC for tax purposes. In the US, the EIN serves both roles: it identifies the entity and acts as the federal tax ID. So one EIN covers what a CRN and a UTR cover together in the UK.
Does ein.so charge for the EIN itself?
No. The IRS charges $0 for an EIN. ein.so charges a service fee to prepare your Form SS-4 correctly, fax it to the IRS at 855-215-1627, and deliver the EIN by email. The fee is $49 Standard (4-7 business days) or $97 Express (2-3 business days). You avoid international IRS phone calls and silent rejections from address errors.
Does a US LLC owned by a UK resident have to file anything each year?
Yes. A foreign-owned single-member US LLC files Form 5472 with a pro-forma Form 1120 each year. The penalty for not filing is $25,000. This is an information return, not always a tax bill. Most US LLCs also file a BOI report with FinCEN. Confirm your specific filings with a US CPA, since ein.so does not provide tax advice.
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